Problem: In 39 years, Tiffany will be 4 times as old as she is right now. How old is she right now?
Explanation: We can use the given information to write down an equation about Tiffany's age. Let Tiffany's age be $t$ In 39 years, she will be $t + 39$ years old. At that time, she will also be $4 t$ years old. Writing this information as an equation, we get: $t + 39 = 4 t$ Solving for $t$ , we get: $3 t = 39$ $t = 13$.